Mancini Massimiliano, Bargiacchi Lavinia, Guido Gisella, Messa Fabiana, Trabalza Marinucci Beatrice, Rendina Erino Angelo, Ibrahim Mohsen, Vecchione Andrea
Morphologic and Molecular Pathology Unit, St. Andrea University Hospital, Sapienza University of Rome, 00189 Rome, Italy.
Department of Medical and Surgical Sciences and Translational Medicine, Faculty of Medicine and Psychology, Sapienza University of Rome, 00189 Rome, Italy.
J Clin Med. 2025 Jun 4;14(11):3968. doi: 10.3390/jcm14113968.
Acute Fibrinous and Organizing Pneumonia (AFOP) is a rare pulmonary condition histologically characterized by intra-alveolar fibrin deposition and organizing pneumonia without hyaline membranes. This study aims to describe the clinicopathologic and radiologic features of isolated AFOP nodules presenting as solitary pulmonary nodules (SPNs) mimicking malignancy in patients with recent COVID-19 infection. We retrospectively analyzed consecutive cases of histologically confirmed AFOP ( = 20) and organizing pneumonia (OP; = 119) presenting radiologically as SPNs suspicious for malignancy from January 2021 to December 2023. Clinical data, COVID-19 status, radiologic features (including nodular characteristics, ground-glass opacity [GGO], and consolidation), and histopathological findings were collected and analyzed. Digital image analysis quantified the intra-alveolar fibrin content. AFOP nodules showed a significant association with previous COVID-19 infection compared to OP (55% vs. 0.8%, < 0.001). Radiologically, AFOP lesions were predominantly located in the upper lobes, frequently exhibiting a mixed pattern of GGO and consolidation within solitary nodules (8-28 mm diameter), distinctly differing from the predominantly lower-lobe homogeneous consolidations in OP. Histologically, AFOP was defined by prominent intra-alveolar fibrin "balls," correlating significantly with radiological consolidation patterns ( = 0.991, < 0.05). Regions of consolidation demonstrated higher fibrin contents compared to areas of predominant GGO. Isolated AFOP nodules presenting as SPNs post-COVID-19 infection strongly mimic malignancy radiologically, highlighting the necessity for multidisciplinary diagnostic approaches integrating radiological and histopathological data to avoid unnecessary interventions. Recognition of this rare but distinctive clinical entity is essential for appropriate patient management.
急性纤维蛋白性机化性肺炎（AFOP）是一种罕见的肺部疾病，组织学特征为肺泡内纤维蛋白沉积和机化性肺炎，无透明膜形成。本研究旨在描述在近期感染新型冠状病毒肺炎（COVID-19）的患者中，表现为孤立性肺结节（SPN）并疑似恶性肿瘤的孤立性AFOP结节的临床病理和放射学特征。我们回顾性分析了2021年1月至2023年12月期间组织学确诊为AFOP（n = 20）和机化性肺炎（OP；n = 119）且放射学表现为疑似恶性肿瘤的SPN的连续病例。收集并分析了临床数据、COVID-19感染情况、放射学特征（包括结节特征、磨玻璃影[GGO]和实变）以及组织病理学结果。数字图像分析对肺泡内纤维蛋白含量进行了量化。与OP相比，AFOP结节与既往COVID-19感染显著相关（55%对0.8%，P < 0.001）。放射学上，AFOP病变主要位于上叶，在孤立结节（直径8 - 28 mm）内常表现为GGO和实变的混合模式，与OP主要位于下叶的均匀实变明显不同。组织学上，AFOP由显著的肺泡内纤维蛋白“球”定义，与放射学实变模式显著相关（r = 0.991，P < 0.05）。与主要为GGO的区域相比，实变区域的纤维蛋白含量更高。COVID-19感染后表现为SPN的孤立性AFOP结节在放射学上强烈疑似恶性肿瘤，突出了整合放射学和组织病理学数据的多学科诊断方法以避免不必要干预的必要性。认识这种罕见但独特的临床实体对于恰当的患者管理至关重要。
